Variations of "How do I learn math?"? Yes, absolutely. Variations of anything math-related but not textbooks or courses? Heck no. It would be foolish of me to ask HN something that is publicly avaliable on the internet.
For example, that's how I found out about mathtutordvd.com in a comment thread for a three year old reddit post.
I have spend a few evenings looking for information on math workbooks, but there just isn't enough of it.
I disagree, what is common are questions or discussions on math books in general which are typically dominated by higher math and material for people already in posession of a stem degree. However many, if not most, math books are not suited for self study. I don't often see discussions on fundamentals or other "unsexy" parts of mathematics.